Electronic messaging systems, such as email systems, have become ubiquitous. While speed and reliability of communications have improved, there is a tendency towards over-communication. People, particularly those whose work is performed with the help of electronic messaging, may send and receive too many messages. This can lead to reduced productivity, in that a person's important messages, which may demand response, may get lost in the clutter of unimportant messages on which the person was merely copied as a matter of precaution or policy. Beyond human concerns, messages consume storage space and network resources, and important and unimportant messages alike must be stored and require network capacity to be sent and received. Network capacity is particularly an issue when messages are sent via wireless communications, as is the case with mobile electronic devices, such as mobile phones and tablet computers.